Devil Fruits

Devil Fruits are mysterious fruits that grow around the One Piece world. They give mysterious powers to those who eat them, however someone who has eaten a devil fruit is no longer able to swim in the sea.

Standard classes
The three main classes of Devil Fruit are Paramecia, Zoan, and Logia. Their effects are these:-

Paramecia - Paramecia class Devil Fruits allows the user to achive a unique power.

Zoan - Zoan class Devil Fruits allow the user to transform between three animal or mythical forms - normal, hybrid, and beast.

Logia - Logia class Devil Fruits mean that you can turn your body into another material and not be hurt by physical attacks.

Syrums & Altered Devil Fruits
The mysterious group known as the Zenkai are able to manipulate devil fruits. To what extent is unknown, but they were able to remove the disability of being unable to swim from one devil fruit. Also, The Zenkai have developed syrums with devil fruit powers in them. This was first shown when Cole injected Red with a special healing syrum.